Many machines, such as, for example, tractors, dozers, and other earth or material moving machines, include tracked undercarriages to facilitate movement of the machines over ground surfaces. Such undercarriages typically include drive sprockets that drive endless track assemblies about one or more idlers, track rollers, and/or other guiding components to propel the machines over the ground surfaces. Each track assembly generally includes a pair of parallel chains, each made up of a series of links, joined to each other by pins and/or bushings (the combination of which is sometimes referred to as a cartridge assembly). Due to extreme wear from abrasion and impacts experienced during use, these components require substantial maintenance, including replacement of worn parts. Such maintenance may be costly.
One significant area of wear for tracked undercarriages is the area where link pins engage guides. The links may include long pin bosses extending laterally toward the outside of the link chain to form sufficient internal surface area to maintain a press-fit of the link with the link pin. A result of this lateral extension of the long pin bosses is that the link pin ends and the long pin bosses encounter a scraping engagement with the guides. This scraping engagement causes wear both to the guide surfaces and to the ends of the link pins and the laterally extending pin bosses. This in turn may weaken the press-fit connection of the link with the link pin. All of this may increase maintenance costs.
A track chain arrangement is disclosed in U.S. Pat. No. 5,183,318 of Taft et al. (the '318 patent). The '318 patent is one example of a track chain arrangement with links that include lateral extensions on the links providing pin bosses surrounding bores for creating ample surface contact with link pins received in the bores. The track chain arrangement of the '318 patent includes a series of link sets connected together by link pins and bushings mounted coaxially around the link pins. An end of each link includes an outboard end collar that forms a long boss extending laterally toward the outside of the link chain. An end of a link pin is pressed and non-rotatably mounted in a bore through the long boss on the outboard end collar. The '318 patent discloses that an additional mechanical interlock may be formed to further prevent any movement between the link pin and the end collar.
The track chain joint of the '318 patent provides a structure and a link pin assembly that ensures a good connection between the link pins and the link sets, but the structure may be improved. The good connection between a link pin and an associated link in the '318 patent requires a pin boss that extends a substantial distance laterally of the link. In many machines, the track chains are pin guided by guiding structure mounted on the undercarriage of the machine. The substantial lateral extent of the pin boss in the '318 patent may make significant contact with the guiding structure and both unduly wear the link pin end and the pin boss and weaken the connection between the link pin and the link.
The track link structure and pin joint assembly of the present disclosure addresses one or more of the needs set forth above and/or other problems of the prior art.